288 HISTORY OF PERSIA CHAP. Khan, which even in decay must rank among the great bridges of the world. Approached by a paved causeway, it is entered through the usual gateway. The extraordinary feature of the bridge, which is 388 yards in length, with a paved roadway 30 feet wide, is that there are three distinct thoroughfares, at three separate levels. One of these is the roadway, on each side of which runs a covered arcade, opening by arches into the main road on one side and on to the river on the other. Here and there this arcade, or gallery, leads past chambers that were originally adorned with paintings. Above this main road, on the summit of the bridge, is a footway reached by steps, and below it a lower storey, to which similar steps descend. Here, just above the river-bed, a passage runs the entire length of the bridge. The only adverse criticism to be made is one which will be appreciated from the illustration, namely, that the bridge at most seasons of the year is a structure too fine for the exiguous stream of the Zenda Rud. Tiles.—The practice of covering buildings with tiles reached its zenith under the Safavi rulers, and this there- fore is a convenient place for a few remarks on the famous products of the Persian kilns. Ceramics certainly played an important part in Achaemenian architecture, and the Frieze of the Archers at Susa, mentioned in Chapter XV., is a superb example of the tiles of the period. But the art apparently disappeared, if, indeed, it was at that time practised on the Iranian plateau, which is doubtful; therefore for our present purpose the tiles of the Achaemenian period may be disregarded. In the first rank is the faience h reflet, or lustred tiles. There is much doubt about the original home of these products, of which the oldest dated pieces, bearing dates A.D. 864-75, are stated to be in Tunis.1 In A.D. 1035 the celebrated Nasiri Khusru gives an interesting account of lustre ware, which apparently did not at that period exist m Iran : but, wherever the art came into being, it is in Persia that it attained a beauty which stamps it for all time as the noblest creation of the potter. What has 1 *7<fe«The Godman Collection" in the Connoiwr for September 1903.